Pumping unit with sliding gear crank arm release



Nov. 5, 1935. w. c. TROUT 2,019,549

PUMPING UNIT WITH SLIDING GEAR CRANK ARM RELEASE Filed May 26, 1931 2 Sheets-Sheet l I In NH bf l/// Q Z I i 2 5 J 2' g gy; 77. 6Q

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PUMPING UNIT WITH SLIDING GEAR CRANKARM RELEASE Filed May 26, 1931 a 2 Sheets-Sheet 2 I ll/l m 9% a0; Ln, Li (3% i? 63 E5 /////j% L18 (Lg.

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Patented Nov. 5, 1935 PATENT A PUMPING UNIT WITH SLIDING GEAR CRANK ARM RELEASE Walter C. Trout, Lufkin, Tex.

Application May 26, 1931, Serial No. 540,084

2 Claims.

The invention relates to an improvement in pumping units of the type which are usually employed with a counter-balanced crank in the production of oil from wells.

In raising the oil from wells there is an unbalanced load on the up stroke of the string of sucker rods which causes an excessive load on the pumping mechanism which has been balanced by the provision of counterbalance weights carried by the crank arm of the pumping unit. Counterbalanced crank arms ofthis type are well known in the art and a typical construction is that known as the Lufkin counter-balanced crank. These crank arms are rotated by means of a pumping unit which is driven by a source of power and adapted to rotate the crank. However, when the well is to be serviced by making repairs to the pump rods or tubing it becomes necessary and economical to release the heavy counterweighted crank from the reduction gears of the pumping unit so that the gears may be driven at a higher rate of speed in order to service the well. The present invention relates to an improvement in the pumping unit construction which enables the quick and simple release of the counterweighted crank from the unit so that the unit may be freed to pull the rods and tubing. The invention here disclosed relates to somewhat the same subject matter as described in the copending application Serial No. 540,090, filed of even date herewith in the name of Guy Croom.

It is one of the objects of the invention to provide a mechanism embodied as part of the pumping unit whereby the counterbalanced crank may be freed from the pumping unit.

Another object of the invention is to provide a longitudinally slidable shaft which is adapted to carry the crank arm and a drive gear therefor.

Another object of the invention is to provide a mechanism whereby the crank arm and its drive gear may be released from the driving gear of the pumping unit so that the crank may remain idle while the pumping unit driving gear is in operation.

A still further object of the invention is to provide a positive driving connection between the pumping unit and the crank arm which connection may be released when the crank is to remain idle.

A still further object of the invention is to provide a two-piece crank shaft for oil well pumping units which is adapted to permit release of the crank arm from the driving mechanism.

A still further object of the invention is to provide a crank shaft which is slidable longitudinally of the pumping unit mechanism in order to release the crank arm from the driving gear.

Other and further objects of the invention will be readily apparent when the following description is considered in connection with the accom- 5 panying drawings wherein Fig. 1 is a central vertical sectional view through the pumping unit mechanism taken along the line of the crank shafts and illustrating a drive mechanism for the pumping unit and the 10 crank shaft.

Fig. 2 is a top plan view of a pumping unit constructed in accordance with the invention and showing the relationship of the parts.

Fig. 3 is a view similar to Fig. 1 and showing a 15 slightly modified form of the invention.

The invention may be best understood by having reference to Fig. 2'where a base for the pumping unit is shown at 3. On this base is mounted a power unit 4, which is adjustable as to its p'osi- 20 tion on the base by means of the slidable supports 5. This power unit is arranged to drive the belt or pulley 6, which is connected with the drive wheel I of the pumping unit. The drive shaft 8 is rotated by the wheel I and is connected with a 25 ge'ar train which composes the principal part .of the pumping unit. This gear train is enclosed within the housing 9 and terminates in an enlarged driving gear l0, which is best seen in Fig.

1. This gear in is arranged to provide power for 30 rotation of the sprocket wheel ll, which receives a chain or other member which leads to the draw works for use in servicing the well. On the opposite end of the crank shaft is mounted the crank arm l2, which is preferably of the counterbal- 5 anced type and which carries the wrist pin 13, to which the pitman rod, walking beam and string of sucker rods are connected. Rotation of this crank arm causes the reciprocation of the string of rods to operate the pump in the well.

Fig. 1 shows the arrangement of the parts inside of the housing 9 and the provision of the double crank shaft so that the crank arm may be released from the driving unit. The housing 9 is formed with an extension l5 which serves as a bearing support and is part of the housing 9' which issu'pported on the base I6. This bearing support I5 is arranged to support the crank arm shaft IT. This shaft is separated from the bearing support by the bearing liner l8 and is adapted for rotation inside of this liner [8. A bearing cap I9 is provided on the end of the bearing support to maintain a seal with the crank arm shaftby means of the packing 20 and 55 lubrication of the shaft is provided by means of lubricant placed in the cavity 2|.

The crank arm 22 is preferably fixed to the crank arm shaft ll by being keyed or otherwise fastened. The inner end of this crank arm shaft I1 carries the crank drive gear 23. This drive gear may be of any desired size and configuration but is preferably provided with external gear teeth 24 on the periphery thereof and has a shoulder 25 adapted to abut against the inner end of the bearing support I5, so that outward movement of the crank arm shaft, the crank arm and the drive gear will be thus limited.

The crank arm 22 may be of any desired type and that illustrated is provided with slots 26 which are arranged to receive a portion of the counterbalance weight which is arranged for sliding movement on the crank arm in a manner now well known in the art.

The pumping unit drive gear l comprises the external teeth 21 which engage with the next gear of the gear train which is driven by the drive wheel 1. This gear includes a hub 28, which is keyed to the gear shaft 29, which is mounted in the bearing support 30, formed in the housing 9 in a manner similar to the bearing support l5. A hearing liner 3! is also provided as well as a bearing cap 32. This gear shaft 29 extends beyond the bearing support and has keyed thereto the sprocket gear H which is arranged to drive the draw works in servicing the well, or for any other use to which the pumping unit may be adapted.

Thrust rings 33 and 34 may be provided at opposite ends of the bearing support 30 to withstand any longitudinal thrust applied to the shaft 29 when the gear 23 is moved.

From the foregoing description it will be apparent that the gear 23 and crank arm 22 are ;rigidly connected together; that the drive gears Ill and the sprocket l I are also rigidly connected together, and that rotation of the drive gear ID will cause rotation of the sprocket ll. However, if rotation of the crank is desired it is necessary to connect the crank drive gear 23 to the pumping unit driven gear l0 and in order to accomplish this the gear i0 is formed with a set of internal gear teeth 35, which are of such size and configuration that they will mesh with the teeth 24 ;on the crank arm drive gear 23. In order that these teeth may mesh, the crank arm I1 is adapted for longitudinal sliding movement in the bearing liner [8, and the mechanism for moving the crank arm shaft longitudinally includes a thrust bolt 36 which is threaded within a thrust cap or plate 31. This plate is preferably attached to the crank 22 by means of fastening elements 38.

The plate is so arranged that it will be confined between the shoulders 39 on the thrust bearing 36 so that upon rotation of the thrust bearing it will be maintained in the same position with respect to the crank arm 22. The thrust bolt 36 is threaded into the cavity 40 in the spindle shaft 4|. This spindle shaft is disposed inside of the crank arm shaft l1 and is of such diameter that it is free from contact with the inside of the crank arm shaft, and extends beyond the drive gear 23 with its inner end mounted in an anti-friction bearing 43 carried in the hub 28 of the drive gear I0. This anti-friction bearing is locked in the driving gear by a plate 44 and the ball race of this anti-friction bearing 43 is locked to the spindle shaft 4| by means of the cap plate 45. With this construction it will be apparent that "q the spindle shaft 4| is prevented from longitudinal movement by its engagement with the hub of the drive gear. It is free to rotate with respect to the drive gear or to remain stationary while the drive gear rotates. When it is desired to engage the driving gear 23 with the driving gear l0 it is only necessary to engage the thrust bolt 36 so that it will be screwed into the spindle shaft and pull the crank arm toward the center of the pumping unit. The entire unit may then be used in pumping the well and when it is desired to release the crank arm from the pumping unit the thrust bolt 36 may be unscrewed so that it will move outwardly with respect to the spindle shaft 4|.

Due to the thrust collars 39, the crank arm 22, the gear 23 will be moved to the right as viewed in Fig. 1. This will disengage the teeth 34 and 35 so that the crank and its associated parts will be freed from the pumping mechanisms. The crank may thus remain idle and the gear l0 rotate with respect to the gear 23 without interference. When servicing of the well or other use of the pumping unit has been completed, the thrust bolt 36 will be rotated to cause engagement of the gears 23 and I0 so that the crank arm will again be connected to the pumping unit. This is a simple and convenient arrangement of the parts for releasing the crank arm and permits circumferential adjustment of the crank arm with respect to the drive gear 10 0, so that the wear on the gears may be uniformly distributed and increased service obtained.

Fig. 3 shows a slightly modified form of the invention in which the essential elements are the same. The arrangement, however, for mounting the gears l0 and 23 has been slightly altered and the bearing support l5 contains the liner l8 which is in direct engagement with a unitary crank shaft 50. This shaft is substantially the same as the crank shafts now used and extends entirely across the pumping unit. The crank arm 22 is rigidly affixed to this shaft as is the drive gear 23 for the crank arm. This shaft 50 is arranged for longitudinal sliding movement in the bearing liner I8 in order to connect and dis- 45 connect the gears I0 and 23. In order that this shaft may be moved, the hub 5| of the gear 23 is provided with a plurality of circumferential ribs 52, which are adapted to engage with the gear teeth 53 on the pinion 54, which is mounted on a stub spindle 55. This spindle may be mounted on suitable bearings, the uppermost of which is indicated at and is carried by the housing 9.

An operative handwheel or handle 51 is also fixed to the shaft so that the pinion 54 may be 5.5 rotated. Rotation of this pinion causes horizontal movement of the hub 5| and corresponding longitudinal movement of the crank shaft 56 so that the gears in and 23 may be engaged or disengaged by movement of this handwheel.

In order that the gear [0 and sprocket ll may rotate with respect to the crank shaft 50, a gear shaft sleeve 58 is provided and to this sleeve the gear I0 is fixed or formed integral. This sleeve 58 is hollow and is provided with bearing liners 59 05 and 60 to support the crank shaft 50. It is to be understood that this gear sleeve 56 is rotatable with respect to the bearing support 3|] and also with respect to the crank shaft 50. The sprocket l l is keyed, as at 60, to this sleeve so that there is a rigid connection between the gear I0 and the sprocket H so that they will rotate together at all times.

With the mechanism constructed as described in this Fig. 3 embodiment the crank shaft 50 extends entirely through the unit and lends a certain rigidity to the device which may be desirable. The gear l0 and sprocket I I are rotatable on this shaft as a bearing and may be connected to the shaft by means of the drive gear 23 when the shaft is moved longitudinally by means of the handwheel 51. When it is desired to use the unit for servicing the well it is only necessary to rotate this handwheel 51 to disengage the crank arm and its associated parts. This mechanism is entirely enclosed in the pumping unit. It is simple and sturdy in its construction and is of particular advantage as it permits a quick alteration of the pumping unit so that it may be used for servicing the well or for pumping the same as desired.

Having described my claim is:

1. A pumping unit for oil wells comprising a housing, a crankshaft projecting from opposite invention, what I sides thereof, a crank arm fixed on one end of said shaft, a toothed clutch member fixed on said shaft within said housing, a drive gear in said housing-rotatably mounted on said shaft, internal teeth on said gear to receive said clutch, and means to shift said shaft longitudinally to engage or disengage said clutch and gear.

2. A pumping unit for oil wells comprising a housing, a crankshaft projecting from opposite sides thereof, a crank arm fixed on one end of said shaft, a toothed clutch member fixed on said shaft within said housing, a drive gear in said housing rotatably mounted on said shaft, internal teeth on said gear to receive said clutch, and means to shift said shaft longitudinally to engage or disengage said clutch and gear, said means including a plurality of circumferential ribs on said clutch and a pinion adapted for rotation.

WALTER C. TROUT. 

